Ground clearance / speed bumps

[CB_83]

Hey all, do any of you Type 65 owners have any experience with speed bumps?
I am in the beginning phases of planning my build and would like to be able to drive the car to work from time to time. Unfortunately the plant where I work is on a private road with 5 speed bumps at the entrance.
My current daily is a 2015 Wrangler on 35"s and a 3.5" lift so it floats right over them, but I could imagine a really low sports car could get beached which would be really uncool!
For reference, the speed bumps are about 3.5" high X 12" long. Just curious how much of an issue things like that and driveway aprons, etc. will be when running one of these cars on the street.

158120

[ggunter]

Most speed bumps they will go right over with no drag if they are the long ones, or the ones that are about 5 ft wide so the front axle rides up over and then the back comes up over. Hard to explain but you know what I mean. The little short narrow ones I usually have to take on an angle to get over them with no drag of the pipes.

[klawrence]

Just hit em at 60, and you will make it over them. In all seriousness you could raise your ride height to clear them, mine is currently at just over 3.5 in the front and 4 in the rear.

[UpNorth]

When I started my build I recall that there was like two settings on the front for the ride height.
I chose the one that gave me higher clearance in order to avoid what you're worried about.
Car is still in paint shop so can't report on the effect yet.

[CB_83]

Thanks for the feedback guys! We used to have really square shaped plastic ones that were pinned to the ground. They were extremely harsh, and even if you didn't drag on them, they were torture on the suspension. Thankfully when they repaved a few years ago they did away with those and put down smoother asphalt ones. The lowest vehicle I've regularly driven was a 2011 Subaru STi at stock ride height. That car had 5.9" of ground clearance per Subaru and never got close to hitting. Guess it'll just be a little trial and hopefully not error when the time comes, lol...

[Logan]

The bottom of the Coupe chassis is totally flat, which is great. Some guys run a little rake, meaning the rear ride height is greater than the front ride height by ~1/2" on average of those I've seen. Other guys run no rake at all, so the same ride height all around.

The static height of the chassis from the ground is how tall of obstacle you could clear. So if you set the coilovers to 4" or 4.5" ride height, you can drive over basically any speed bump you'll find without scraping. Alao no need to drive at an angle, although I recommend about 2-10mph rather than 60mph.... Lol

[J R Jones]

The bottom of the Coupe chassis is totally flat, which is great. Some guys run a little rake, meaning the rear ride height is greater than the front ride height by ~1/2" on average of those I've seen. Other guys run no rake at all, so the same ride height all around.

The static height of the chassis from the ground is how tall of obstacle you could clear. So if you set the coilovers to 4" or 4.5" ride height, you can drive over basically any speed bump you'll find without scraping. Alao no need to drive at an angle, although I recommend about 2-10mph rather than 60mph.... Lol

Logan, You have mentioned static height and speed, but together there is a vertical displacement that may consume ride height. When the suspension jounces going up a bump, it unlikely to be a problem, however, coming off the bump the weight of the car can jounce the suspension as it rolls onto the flat, consuming ride height. This could cause bump contact behind the front and rear tires.

We ran the La Carrera Pan America race across Mexico several years ago. All the towns had speed bumps (topaes) especially on entry. We had to slow appropriately as a factory Mercedes 300SL Gullwing approached from the rear. He was flashing lights and horn beeping so I waved him around. He accelerated past on the left to find the topae. He hit it so hard I saw air under all four tires.
jim

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[NAZ]

Have you considered 35" tires, skid plates, and a 3.5" lift? That seems to work on your Jeep.

So the obvious answer is simply adjust ride height to accommodate the roads you'll be driving. Every build has trade-offs. You'll find the right compromise that works for your car and road hazards.

Have fun.

[Logan]

Logan, You have mentioned static height and speed, but together there is a vertical displacement that may consume ride height. When the suspension jounces going up a bump, it unlikely to be a problem, however, coming off the bump the weight of the car can jounce the suspension as it rolls onto the flat, consuming ride height. This could cause bump contact behind the front and rear tires.

Good addition, Jim. In a softly sprung and damped vehicle, you could compress the suspension after each axle crosses the speed bump. I would expect even the stock spring rates of the Coupe to be stiff enough to limit this jounce to a pretty small amount. And any increase in spring rate or shock rebound would further reduce the effect.

All of this is pretty academic, and I doubt you'd ever have any issue with a speed bump in reality. And of course you can always use the angled approach trick. Suffice to say, I don't think you should let potential speed bumps influence the purchase of a Factory Five. Let the build commence!

[CB_83]

Cool, thanks for the info all! Yeah this never would've been a deal breaker for me, just something to plan for/around with ride height and whatnot.
I just didn't want to be "that guy" in 2-3 years driving to work and needing to grab the forklift to to get past the bumps, lol...

[Erik W. Treves]

In 4+ years of street driving - I am 4 1/4 in the front and 4 1/2 pass - 4 5/8 driver side in the rear (wit - my bellhousing hangs below the frame about 1/2 inch - I scrape at the housing if I "attack" the speed bump - if I slow down and just roll over it - no problems - the approach angle on the nose though is another area you want to watch and be careful of.... all in all at normal street height I haven't had any issues - if you are worried - get a couple STANCE pucks for the front and you will be set - I have them on my GTM and they work great!

[Olli]

When I started my build I recall that there was like two settings on the front for the ride height.
I chose the one that gave me higher clearance in order to avoid what you're worried about.
Car is still in paint shop so can't report on the effect yet.

????? Two settings? Are you referring to control arm location? Ride height is set with the coilovers' adjusting collar. You may want to revisit your suspension installation.

[David Williamson]

on the Gen 3 coupe there are 2 sets of holes that the suspension can be bolted to. One for street and another for a low race track setup.
David W

[Jhamilton]

I have a 65' Coupe, the clearance is low and mine is worse so, because I have the explosion proof bell housing. It scrapes on neatly ever speed bump. I increased the ride height of 65' by puttin 28" tires. This fixed the problem completely.

A local race shop recommended I could grind the bell housing in lieu of taller tires or get a $6k lift kit - which is an expensive solution of a 2 second problem.

I posted my tire change out and results here on the forum, under Coupe tires.

[cgundermann]

In 4+ years of street driving - I am 4 1/4 in the front and 4 1/2 pass - 4 5/8 driver side in the rear (wit - my bellhousing hangs below the frame about 1/2 inch - I scrape at the housing if I "attack" the speed bump - if I slow down and just roll over it - no problems - the approach angle on the nose though is another area you want to watch and be careful of.... all in all at normal street height I haven't had any issues - if you are worried - get a couple STANCE pucks for the front and you will be set - I have them on my GTM and they work great!

Erik - after checking out Stance parts, will they work with the Koni's horizontal top post mounting? Or do you switch to a vertical threaded mount shock/assembly. I'm assuming the Daytona mounts the Konis like the MK4.

Chris